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Spark Test (GS400, LS400 & SC400)

CAUTION: To prevent fuel from being injected during cranking in the following procedure, crank engine for no more than 5-10 seconds at a time.
  1. Disconnect ignition coil connector. Disconnect injector connector for cylinder being tested. Remove ignition coil to be checked. Remove spark plug. Connect spark plug to coil and reconnect ignition coil connector. Ground the spark plug.
  2. Check plug for spark while cranking engine. If spark is not present, turn ignition off. Check ignition coil and ignitor connectors. Repair as necessary. If connections are good, substitute another ignition coil with ignitor and recheck system operation.
  3. If problem persists, turn ignition on. Using a voltmeter, check for battery voltage between ground and positive terminal (Black/White wire on GS400 and SC400 or Black/Red wire on LS400) at ignition coil connector.
  4. If battery voltage is not present, repair circuit between ignition switch and ignition coil or ignitor. If battery voltage is present, check resistance between terminals of Camshaft Position (CMP) sensor. See SENSOR RESISTANCE  table. If resistance is not as specified, replace CMP sensor. If resistance is as specified, check resistance between terminals of Crankshaft Position (CKP) sensor. See SENSOR RESISTANCE  table.
  5. If resistance is not as specified, replace CKP sensor. If resistance is as specified, check for ignitor circuit malfunction (IGT signal). If IGT signal from ECM is defective a Diagnostic Trouble Code (DTC) should set in ECM memory. See testing procedure for DTC P1300 in TESTS W/CODES article. If IGT signal circuit is okay, substitute another ignition coil with ignitor and recheck system operation.
IGNITION COIL RESISTANCE

Application Primary Secondary
Aisan (3)
Cold (1) .70-.94 10,800-14,900
Hot (2) .85-1.10 13,100-17,500
Diamond (3)
Cold (1) .70-.94 6,800-11,700
Hot (2) .85-1.10 8,600-13,700
(1) Coil temperature of 14-122°F (-10-50°C).
(2) Coil temperature of 123-212°F (51-100°C).
(3) Name of ignition coil manufacturer.
IGNITION COIL RESISTANCE

Application Primary Secondary
Cold (1) .33-.52 8,500-14,700
Hot (2) .42-.61 10,800-17,200
(1) Coil temperature of 14-122°F (-10-50°C).
(2) Coil temperature of 123-212°F (51-100°C).
SENSOR RESISTANCE

Application Ohms
Camshaft Sensor
Cold (1) 835-1400
Hot (2) 1060-1645
Crankshaft Sensor
Cold (1) 1630-2740
Hot (2) 2065-3225
(1) Sensor temperature of 14-122°F (-10-50°C).
(2) Sensor temperature of 123-212°F (51-100°C).
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